class Container {
  final int width;
  final int height;

  const Container({required this.width, required this.height});
}

void main(List<String> args) {
  var o1 = new Object();
  var o2 = new Object();
  print(identical(o1, o2)); // false

  var c1 = const Container(width: 100, height: 100);
  var c2 = const Container(width: 100, height: 100);
  print(identical(c1, c2)); // true

  var c3 = const Container(width: 100, height: 100);
  var c4 = const Container(width: 120, height: 120);
  print(identical(c3, c4)); // false
}